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User Authentication via PRNU-based Physical Unclonable Functions
No full textMultifactor user authentication systems enhance security by augmenting passwords with the verification of additional pieces of information such as the possession of a particular device. This paper presents an innovative user authentication scheme that verifies the possession of one's smartphone by uniquely identifying its camera. High-frequency components of the photo-response nonuniformity of the optical sensor are extracted from raw images and used as a weak physical unclonable function. A novel scheme for efficient transmission and server-side verification is also designed based on adaptive random projections and on an innovative fuzzy extractor using polar codes. The security of the system is thoroughly analyzed under different attack scenarios both theoretically and experimentally
Evaluating the influence of mechanical stress on anticancer treatments through a multiphase porous media model
No full textDrug resistance is one of the leading causes of poor therapy outcomes in cancer. As several chemotherapeutics are designed to target rapidly dividing cells, the presence of a low-proliferating cell population contributes significantly to treatment resistance. Interestingly, recent studies have shown that compressive stresses acting on tumor spheroids are able to hinder cell proliferation, through a mechanism of growth inhibition. However, studies analyzing the influence of mechanical compression on therapeutic treatment efficacy have still to be performed. In this work, we start from an existing mathematical model for avascular tumors, including the description of mechanical compression. We introduce governing equations for transport and uptake of a chemotherapeutic agent, acting on cell proliferation. Then, model equations are adapted for tumor spheroids and the combined effect of compressive stresses and drug action is investigated. Interestingly, we find that the variation in tumor spheroid volume, due to the presence of a drug targeting cell proliferation, considerably depends on the compressive stress level of the cell aggregate. Our results suggest that mechanical compression of tumors may compromise the efficacy of chemotherapeutic agents. In particular, a drug dose that is effective in reducing tumor volume for stress-free conditions may not perform equally well in a mechanically compressed environment
Techniques and Experimental Results for Performance Analysis of Photovoltaic Modules Installed in Buildings
No full textPhotovotaic (PV) modules applied to buildings form a unique surface at the same roof inclination, replacing the tiles. Such PV systems are affected by thermal and mechanical stresses, and remarkable dirt. Another issue is the partial shading with possible failure of bypass diodes. In this paper a sample of PV modules, affected by the previous issues, was tested by electroluminescence and I-V curve scanning, to quantify power losses according to the causes. The experimental results are presented, demonstrating that the most important causes of losses are the cracks in module's solar cells and the failure of their bypass diodes
Measurement of azimuthal correlations of D mesons with charged particles in pp collisions at √s=7 TeV and p-Pb collisions at √sNN=5.02 TeV
No full textThe azimuthal correlations of D mesons with charged particles were measured with the ALICE apparatus in pp collisions at s√=7 TeVs=7 TeV and p-Pb collisions at sNN‾‾‾√=5.02 TeVsNN=5.02 TeV at the Large Hadron Collider. D0D0 , D+D+ , and D∗+D∗+ mesons and their charge conjugates with transverse momentum 3<pT<16 GeV/c3<pT<16 GeV/c and rapidity in the nucleon-nucleon centre-of-mass system |ycms|<0.5|ycms|<0.5 (pp collisions) and −0.96<ycms<0.04−0.96<ycms<0.04 (p-Pb collisions) were correlated to charged particles with pT>0.3 GeV/cpT>0.3 GeV/c . The yield of charged particles in the correlation peak induced by the jet containing the D meson and the peak width are compatible within uncertainties in the two collision systems. The data are described within uncertainties by Monte-Carlo simulations based on PYTHIA, POWHEG, and EPOS 3 event generators
Ductility of lightly reinforced and fiber-reinforced concrete elements: A unified approach
No full textLightly Reinforced Concrete (LRC), Fiber-Reinforced Concrete (FRC), and Hybrid Reinforced Concrete (HRC) elements subjected to static bending actions exhibit a similar behavior, which depends on the amount of rebar and/or fibers added to the cementitious matrix. In all the cases, if a suitable reinforcing system is not provided, the brittle failure occurs at the cracking of concrete. Hence, a new and unified approach is introduced in the present thesis to evaluate the minimum reinforcement for static reasons. Such approach is based on the definition of the ductility index ( DI ), which is a function of the difference between the ultimate load and the effective cracking load. Therefore, DI is higher than zero when a lightly reinforced member shows a ductile response, whereas it is negative in case of brittle behavior. To study the brittle/ductile transition (i.e., the minimum reinforcement), the flexural behavior of concrete beams containing low amounts of rebar, fibers, or a combination, is predicted through three general models for LRC, FRC, and HRC members. In addition, test results coming from the available literature and a specific experimental campaign are considered. Both numerical and experimental data reveal the existence of a generally valid linear envelope of DI when the reinforcement varies in a concrete member. Based on these results, a design-by-testing procedure can be established for determining the minimum reinforcement of a LRC and/or FRC element, which corresponds to DI equal to zero. Moreover, the minimum reinforcement of an HRC element is defined by any linear combination of the associated minimum amounts of sole rebar and fibers. The proposed approach is adopted to design the minimum reinforcement of precast concrete segments for a tunnel lining. It is applied to LRC, FRC, and HRC members, not only subjected to pure flexure but also under combined axial force and bending moment. Finally, the ductility index is used as functional unit of a simplified sustainability analysis. In the specific case of lightweight FRC one-way plates, this new parameter allows to measure the performances of the concrete elements in combined ecological and mechanical analyses, with an integrated holistic approach
THE COMMON EVOLUTION OF GEOMETRY AND ARCHITECTURE FROM A GEODETIC POINT OF VIEW
No full textThroughout history the link between geometry and architecture has been strong and while architects have used mathematics to construct their buildings, geometry has always been the essential tool allowing them to choose spatial shapes which are aesthetically appropriate. Sometimes it is geometry which drives architectural choices, but at other times it is architectural innovation which facilitates the emergence of new ideas in geometry. Among the best known types of geometry (Euclidean, projective, analytical, Topology, descriptive, fractal,…) those most frequently employed in architectural design are: (1) Euclidean Geometry (2) Projective Geometry (3) The non-Euclidean geometries. Entire architectural periods are linked to specific types of geometry. Euclidean geometry, for example, was the basis for architectural styles from Antiquity through to the Romanesque period. Perspective and Projective geometry, for their part, were important from the Gothic period through the Renaissance and into the Baroque and Neo-classical eras, while non-Euclidean geometries characterize modern architecture
A parametric fire risk assessment method supporting performance based approaches application to health-care facilities in northern italy
No full textFire risk assessment has always been a challenging issue. Furthermore, performance based approaches to fire engineering showed that risk based decisions and fire scenarios are a fundamental element of the fire safety strategy assurance. In particular, a correct assessment of the risk allows all the involved stakeholders to identify a specific strategy among a pool of possibilities. Risk assessment is the perfect tool to identify comparable fire protection strategies and to measure fire risk reduction associated to the single specific prevention and protection measures composing each different fire strategies. This approach implies the need to abandon a classic, not even conservative approach, that in many cases linked the total fire load to the fire risk level, despite specific dynamics, layouts, prevention measures and risk management issues during time. During the years, a number of different methodologies have been developed: for specific cases, for industrial or civil buildings, to adopt a method enforced by the local law and regulations acts, etc. Methods have been based on matrices, indexes, check-lists, etc. Present paper illustrates a method developed by the authors taking into account several international recognized methods; even coming back to methodologies developed in early seventies. The Method is named "FLAME" (Fire risk Assessment Method for Enterprises), it goes back to the fire safety fundamentals against a generalized approach to fire safety engineering based on complex and time-consuming methods like CFD that deals only with the ‘consequences' aspect of the fire risk (that is indeed characterized also by frequency estimation) using as reference scheme the "Fire Safety Concept Tree" explained in detail in the NFPA 550 Standard. In order to identify the most appropriate fire safety strategy it is important to identify the associated fire risk that the strategy is intended to mitigate to a certain level. Alternative solutions can be evaluated considering the risk reduction operated by different strategies and by different elements composing the fire strategies themselves and also costs with a modern ALARP approach. A clear advantage is the possibility to get an overview of the whole fire risk as the cumulative risk assessed by the model and not solely related with the consequences evaluation of a limited number of fire scenarios (usually the most obvious ones). Risk level assessment leads to the identification of the fire scenario (or a pool of) that governs and limits the specific situation, declined for both humans and structures (assets) considering that the two vulnerabilities could be linked to different fire risk scenarios. The method has been tested against different buildings occupancies. In the present case results of the FLAME method application to hospitals and health-care facilities are reported. A fire compartment-based risk estimation has been conducted on an overall of about 300 compartments (overall size of about 60000 m 2 ). Coherence has been found among risk estimation by FLAME parametric code and prescriptions of the Italian fire code. There is good agreement when assessing the RSET with the method proposed in FLAME, dealing with the occupants' behaviour and the actual characteristics of occupants in clinics or hospitals and difficulties due to poor mobility or incapacity to understand emergency cues
